The military leaders, in power since a 2014 coup, said immigration officials had made the decision to bar him, although no reason for doing so was given.

China’s Foreign Ministry said it had noted the reports and respected Thailand’s immigration control.

Wong, 19, was at the heart of the mass demonstrations against Chinese influence, known as the Umbrella Movement, which brought parts of Hong Kong to a standstill for nearly three months.

The protestors were calling for free elections for Hong Kong’s leadership, without influence from Beijing. The protests ultimately failed to achieve their goal, but several of their leaders have since entered politics.

A Thai Foreign Ministry spokesman said entry into Thailand “has to be in line with the relevant immigration laws and regulations”.